Name the smallest sized organism.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks for the name of the smallest sized organism. This requires knowledge of various organisms and their sizes.

2. **Identifying the Organism**: The smallest known organism is Mycoplasma. It is a type of bacteria that lacks a cell wall and is known for its small size.

3. **Size Specification**: Mycoplasma species, particularly Mycoplasma pneumoniae, have a size ranging from approximately 0.1 to 0.5 micrometers (µm). This size range makes them the smallest known organisms.

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